1. Technical Field
The present invention generally relates to packaging equipment and, more particularly, to machinery that fills and seals plastic bags. Specifically, the present invention is directed to a bag handling machine that automatically opens, fills, and seals wicketed plastic bags for the food industry. The application also relates to methods for handling the bags as the bags are being opened, filled, and sealed.
2. Background Information
Packaging various items in plastic bags is becoming increasingly popular in the packaging and food packaging industry. Plastic bags are inexpensive to manufacture and have the ability to keep food fresher than other types of traditional packaging. Some types of plastic bags may include a resealable closure. Problems have occurred in the food industry in filling these bags leading some packaging companies to fill the bags by hand. Filling bags by hand is expensive and increases the probability of food contamination.
It is desired in the art to provide an automated machine that fills plastic bags with food items and seals the plastic bag in a sanitary environment. Such machines are governed by numerous governmental restrictions relevant to food handling. For instance, all food handling equipment must be disposed a minimum distance above any floor surface. Any food that is dropped onto the ground obviously must be discarded for sanitary purposes. Various other limitations known in the art govern the design of this type of automated equipment. The limitation regarding the height of the food items above the floor increases the importance of the height of the apparatus and the loss of height that occurs during the process performed by the apparatus. This importance is magnified when the machine is installed in a building with a low ceiling. It is thus desired in the art to provide a bag filling and sealing apparatus that performs its process while losing little vertical height in the flow of the bag. Such a machine provides maximum head room for the equipment that it is being attached to.
Other important design considerations include the desire to eliminate wasted bags, wasted food, and wasted time. As such, the machine should generally move the bags quickly through the process of filling and sealing, eliminate broken bags that must be discarded, and eliminate misfires that cause the food to be dropped onto the ground.
Another problem that has arisen with the use of bags to package food is particularly evident with bags having lower gussets that form a broad based bag. These bags are desired in the art because they may stand vertically on their own after they have been filled and can accept a relatively large amount of food in a small space and without damaging the food. Unfortunately, a rather significant amount of force is sometimes required to open the gussets to their open position. This relatively large amount of force may be easily created when the food items are relatively heavy but difficult to achieve when the food items are relatively light. Light food items may include various types of snack foods such as popcorn that occupy a large volume while weighing relatively little. It is thus desired in the art to provide an apparatus that ensures that the bottom gussets of these types of bags open prior to filling the bags with the food item.
Another problem with prior art bag filling machinery is that the wickets or bag holders used to hold the bags before they are filled often cause the bags to wrinkle and tear as they are being pulled off of the holder. Such prior art bag holders typically include a right angle junction where the bags are being pulled from the holder. It has been found that this junction tends to wrinkle the plastic of the bag at the junction and causes the corner seams of the bag to tear as the bag is being pulled from the holder.
Another problem with prior art devices is that some bags must be evacuated prior to sealing. This has created problems because the top of the bag must be substantially closed prior to evacuating the bag. It is thus desired in the art to provide a configuration that allows the bags to be easily evacuated just prior to sealing the bags.